No. YIT.] 


{SECOND SERIES. 


Solid Steel Castings 

FOR 


Ordnance, Structures, and General Machinery, 


BY 


The Terrenoire Process. 


DETAILED SPECIFICATION OF THE MATERIALS, FURNACE 

PRACTICE, TESTS, ETC. 



. i 

Note.—T his Report is printed for private circulation. 

i/ 

A. L. HOLLEY. 


New York, November, 1877. 


/ * 




I take pleasure in stating that the greater part of this 
Report was compiled by my assistant, Mr. Laureau, from my 
notes (covering some two weeks’ observations) and from his 
own, and from data which I have since received from Terre- 
noire. As Mr. Laureau remained a month in Terrenoire 
after I left, his observations and knowledge of the process 
became very complete and practical. 


Copyright, 

1877, 

By A. L. HOLLEY, 






Solid 



The most remarkable of the several revolutionary develop¬ 
ments of the steel manufacture during: the last few years is 
undoubtedly the production, at Terrenoire, in France, of solid 
castings, without blow-holes, in malleable steel —castings which, 
after no other treatment than annealing:, have the strength. 

n’ o 7 

specific gravity, and physical qualities generally, ot forged 
steel. The harder variety, in the shape of shells, goes with¬ 
out breaking through armor-plates which injure chilled-iron 
shells and even hammered-steel shells in a greater degree, and 
the softer varieties bend double cold and stretch 25 per cent, 
and more in tension, like rolled steel boiler-plates. 

Two circumstances seem to define the status of this im¬ 
provement—to put it in the list of established rather than of 
experimental manufactures: 1st. It is the result of no less than 
ten years’ gradual development. Many new processes show 
spasmodic results of great promise, the essential conditions of 
which cannot be determined nor maintained in regular prac¬ 
tice. This process, on the contrary, like all standard improve¬ 
ments, has been worked out through numerous difficulties, at 
great cost, and with the constant aid of both chemical and 
physical analyses.* 2d. The manufacture of solid steel cast¬ 
ings, chiefly projectiles, has been carried on regularly above 
two years, and the process, as finally perfected and formulated, 
has not been changed during that time. An exact chemical 
process has been reached and adhered to. 


* In July, 1874, as stated in my Report No. 8, First Series: “I saw 
some test pieces (of steel castings) eight to ten inches square, which were 
as sound as any iron castings, although malleable.” 


> 

) 


) 

* 


* 

> 




i V'j'Ma 








4 


Immediately after the French Exposition oi 1867 a series of 
experiments were undertaken at Terrenoire, with a view to 
produce a metal which would meet the requirements of pro¬ 
jectiles for naval guns. These experiments led the engineers 
in charge into a new field of investigations, and resulted in 
the discovery of a sure and regular method of obtaining steel 
castings without blow-holes. Sound steel castings cannot 
now, indeed, be claimed as altogether novel ; castings are 
obtained every day in which blow-holes are nearly avoided. 
Some Sheffield firms devote themselves almost exclusively to 
this kind of work, and the Krupp ingots, as shown at several 
exhibitions, have demonstrated the possibility of producing 
solid steel castings. But there is between these products and 
the Terrenoire metal a wide difference: the Sheffield and 
Krupp castings are melted in crucibles, they are veiy hard, 
and, in spite of the long annealing they usually undergo, they 
show but little ductility and toughness. The Terrenoire 
metal, on the other hand, is produced cheaply in the Siemens 
furnace, and possesses, in the cast state, all the necessary quali¬ 
ties for industrial and structural purposes: it is soft and 
malleable, and as strong as ordinary steel of the same grade is 
after rolling or hammering, and, strange to say, its density is 
always as high as and sometimes higher than that of ordinary 
forged steel. These statements, startling as they may be, are 
supported by fficts developed in numerous experiments made 
by the Terrenoire engineers in developing the manufacture, 
and by the French Government in testing it. 

It is proposed in this paper, 1st, to state briefly the investi¬ 
gations which led to the present result; 2d, a specification of 
the operation in the open-hearth furnace for both hard and 
soft steels, including the tests and analyses of the materials em¬ 
ployed and products obtained ; 3d, illustrations of the process 
by the details of a number of operations which were witnessed 
by my assistant and myself; 4th, the operation in the Besse¬ 
mer converter and in the crucible; 5th, the theory of the pro 
cess; 6th, some facts about moulds and on annealino-; and. 
7th, some considerations regarding the uses of solid steel 
castings. 



6 


THE PRELIMINARY INVESTIGATIONS. 


There were at the Paris Exposition in 1867 some large pro¬ 
jectiles, said to be made of chilled cast-iron, which, it was 
stated, could perforate thick armor-plates. They came from 
Gradatz in Styria, and Finspung in Sweden. The French navy 
tried them, and found that they positively went through the 
thickest armor-plates then known. Several French works 
were recpiested to attempt the manufacture of a similar pro¬ 
duct, and Terrenoire, among others, started a series of experi¬ 
ments which we will follow in some detail. The problem 
was an interesting one, inasmuch as up to that time hardness 
and brittleness were, as far as cast-iron is concerned, considered 
as synonymous terms. 

•/ «y 

One of the first things to be determined was the influence of 


a metallic mould on cast-iron. For this purpose some cylin¬ 
ders 225 millim. (about 9 iii.) in diam. were cast; they were 
placed between bearings 50 centim. (19^ in.) apart ; a ram 
weighing 400 kilog. (882 lbs.) was then dropped upon them 
from different heights. The following are the results of the 
first experiments: 


Description. 

Cast in Sand. 

Chilled. 

TIpqspo’ps Iron Tirol, p fit. . 

13 ft. IK in- 

4 ft. 11 in. 

Qt riprvftis iron flt,. 

14 “ 93| “ 

4 “ 11 “ 



These results were expected, and it was evident that some 
other and special means had been used to produce these strong 
projectiles. An analysis of one of them showed the unusually 
small carbon percentage of 2.94. A low carbon pig had obvi- 
ously been used as a starting-point, or else the metal had been 
decarburized by some special process. The Siemens furnace 
was then brought into use, and a number of different irons 
were tried with the addition of a certain amount of steel-scrap 
before casting. 














The following drop-tests were obtained from the 882-lb. 
ram, supports 19^ in. apart: 


Description. 

Cast in Sand. 

Chilled. 

Charge No. 622—1,500 lbs. Terrenoire iron, 
with 600 lbs. scrap. 

18 ft. 

11 ft. 5 in. 

Charge No. 832—1,500 lbs. St. Gervais iron, 
with 600 lbs. scrap. 

15 ft. 7 in. 

8 ft. 2 in. 

Charge No. 688—1,500 lbs. Givors iron, with 
600 lbs. scrap . 

13 ft. 134 in. 

13 ft. in. 

9 ft. 10 in. 

Charge No. 879—1,500 lbs. Givors iron, with 
600 lbs. scrap. 

18 ft. 



Tlmse results showed that the addition of scrap improved 
the iron when either cast in sand or chilled. 

But while these experiments gave important information 
regarding the problem in hand, they also opened the way to 
the manufacture of solid cast-steel. The considerable varia¬ 
tion in the breaking-points of the different test pieces, after 
careful consideration, was found to correspond with the 
amounts of silicon they contained; the strongest invariably 
contained the largest amount of silicon. Charge 832, which 
shows a weak chilled test, is made of St. Gervais pig, in which 
almost no silicon is found. The Givors pig used in Charge 
(388 contains only 1.36 per cent, of silicon, while the iron used 
in 879 contains 3.22 per cent. Numerous other experiments 
showed that these results were regularly obtained, and that 
the strength was always in proportion to the amount of silicon 
in the pig. 

It was further ascertained that when the addition of scrap 
was pushed beyond a certain limit, bubbling (and hence blow¬ 
holes) began to appear, and that the time of the bubbling va¬ 
ried with the proportion of silicon in the pig. This discoverv 
was a very important one; it gave a clear idea of the action 
of silicon, so necessary in the manufacture of steel without 
blow-holes. After a number of careful experiments, some 
projectiles made of this mixed metal were sent to Gavres and 
subjected to trial. On the 13th of December, 1869, two 9*4-in. 

















7 


solid projectiles were fired at a 6-inch armor-plate at a speed 
of 1,036 ft. per second. They went through the plate with¬ 
out any deformation whatever. On January 18, 1870, a trial 
was made with 9-in. shells. They were fired at the 6-in. 
plate with a speed of 1,040 feet, and they went through the 
plate as well as the solid projectiles had done. These trials, 
though satisfactory in themselves, were not conclusive ; the 
Commission insisted upon testing the projectiles in oblique 
firing, which was done on the 19th of April, 1870. Two 9]/ 2 - 
in. solid projectiles were fired at a 6-in. plate standing at an 
angle of 20° from the perpendicular, but were broken. Sub¬ 
sequent trials gave the same results. When a solid projectile 
is used, it does not matter much whether it breaks or not, as 
long as it goes through the plate ; but a shell should go through 
whole and burst on the other side. The problem was therefore 
unsolved, and the Terrenoire engineers clearly saw that their 
mixed metal could not answer. 

They then resolved upon producing a cast metal hard 
enough not to be deformed by the blow, and ductile enough 
not to break; in other words, a real steel. Their previous 
experience had shown the action of silicon ; they were con¬ 
vinced that the more siliconized a pig is, the larger amount of 
scrap it will bear before the special state of oxidation occurs 
which produces blow-holes. Guided by this knowledge, they 
used for the initial bath a pig containing more than 8 per 
cent, of silicon and some manganese. They succeeded by this 
method in obtaining a fair product, but it lacked uniformity, 
as it was very difficult to get a true idea of the composition of 
the bath at the end of the operation. 

It then occurred to them that the most rational method 
would be to follow the regular Martin practice, by decarbu- 
rizing an initial bath to the required point, and then correcting 
the oxidation by silicious pig. After a good many prelimi¬ 
nary failures they finally determined that, in order to obtain 
steel without blow-holes, a proportion of 11 to 12 per cent, of 
a pig containing 3.5 to 4.0 of silicon should be added. Lhis 
proportion should vary according to the degree of hardness 
required. The product was regularly without blow-holes, and 


8 


gave the following tons’ resistance per square inch in the test¬ 
ing-machine : 



Raw metal. 

Tempered in oil. 

Elastic limit. 

19.68 to 20.95 * 

37.10 to 40.27 

Breaking load. 

80.48 to 31.50 

46.45 to 50.8 

Stretching. 

1.5 % 

O 

o 

o 

o 

© 


These results indicate a very hard metal, unfit for most 

uses except projectiles. The experiments had taken so much 

time that no firing trials were made until July, 1872. Then 

two unannealed 9^-in. projectiles were fired at an 8-in. plate. 

They went through without breaking, but the rounded part 

was upset from 1 ]/ A to 1 yi inch. The cylindrical part was 

unchanged. These results, though encouraging, did not seem 

sufficient, and new experiments had to be made in order to 

obtain a metal which, though a little harder, would be less 

deformed bv the blow. 

•/ 

The process, too, was unsatisfactory ; the metal was pasty, 
it ran very badly, and did not stand forging very well. A 
special study of the question showed that this pasty state of 
the metal was due to the addition of silicious pig. The sili¬ 
con, in being oxidized to silica, prevented the formation of car¬ 
bonic oxide and blow-holes; but this silica, in presence of so 
much iron, formed silicates, which to a great extent remained 
in the bath. TIence the lack of fluidity as well as the infe¬ 
riority of the metal; the interposed slag must necessarily de¬ 
crease its strength and ductility. 

The cause of the defect once known, the remedy determined 
upon was the final addition of some substance which would 
make the slag sufficiently fluid to separate from the metal. 
Manganese was found to be the right material, not only on 
account of the fluid slag it forms, but also on account of the 
qualities it imparts to the steel. 

The final improvement was the introduction of a certain 
amount of manganese in the initial bath, the function of which 
is to keep down oxidation from the start, for the following 

o 





















9 


reason : It oxygen is allowed to go on accumulating in the 
bath, it is impossible to tell how much there is of it present 
when the final additions of silicon and manganese are made, 
and how much of these substances will be removed in taking 
up this oxygen. Therefore oxygen must be kept out, so that 
the whole of the ingredients finally added shall be left to per¬ 
form their work. 

All these modifications were the work of years ; it was not 
until 1875 that the Terrenoire Company reached their aim— 
the production of a cast-steel shell * which should go unharmed 
through an armor-plate and burst on the other side. On Sep¬ 
tember 24, 1875, two 9*4-in. shells were fired normally at an 
8^-in. armor-plate, and another shell of the same size was 
fired at an angle of 20° at an 8-in. plate, with a speed of 1,280 
ft. The three shells went through and were found respect¬ 
ively at the following distances behind the blocking: 710 ft., 
895 ft., and 2,060 ft. The rounded ends were compressed 
from % to f /2 inch. On January 8, 1876, three 9shells 
were fired at angles of 28° and 30°. The plate was 8 inches 
thick and the initial speed 1,390 ft. The three projectiles 
perforated the plates and were found behind the blocking at 
the following distances: 1,302 ft., 2,952 ft., and 3,608 ft. 
Two of these shells were compressed about ]/ 2 in., and showed 
a swelling at the circumference of y in. ; the third one, made 
purposely of a softer metal, was compressed l l /± in. and bulged 
out of an inch. These were perfectly satisfactory results, 
for the inside chamber was of the regulation size, and firing 
had been tried at a maximum angle. 

Had the Terrenoire engineers stopped their investigations at 
this point, and produced a metal fit only for the manufacture 
of projectiles, their discovery could not have been considered, 
from an industrial standpoint, as of the highest importance. 
But, following up the line of experiments, they succeeded in 
producing all varieties of steel castings without blow-holes, 
from very soft to very hard, as surely and regularly as ingots 
are made. 

* An engraving of the Terrenoire shell is appended. It is cast solid 
and bored out. The chamber is plugged with steel of the same kind. 


10 


The chemical and mechanical qualities of the perfected 
metal are shown in Table A, and also in the large table at the 
end of this Report. In the latter the results of annealed and 
oil-hardened metal only are given. In Table A the results 
of raw, annealed, and hardened metal are stated, and from 
this table we derive the following facts: 

1st. That the chemical composition of this metal is widely 
different from that of ordinary steel. 

2d. That its average tensile resistance in a cast and annealed 
state—which we shall afterwards observe to be the normal 
state of steel without blow-holes—is as follows: 

Hard Steel, 47.51 tons per sq. in. and 8.1$ elongation. 

Medium “ 46.92 “ “ 14.6$ 

Soft “ 81.72 “ “ 25.3$ 

This is fully up to the standard of hammered Siemens- 
Martin steel. 

These remarkable averages do not bear on a few experi¬ 
mental heats only, but on a whole series of operations made 
in the regular practice at the works, and for commercial 
purposes. 


TABLE A. 

Strength of Solid Steel Castings, Raw , Annealed, and Hardened. 


Description. 

Analysis 

1 | 

Raw Metal. 

I 

Metal cooled 

Annealed Meta..! 

nealed. 

1 

C. 

1 

Si. 

1 

1 Op 

Mn. tg*§ 

■S3 

Breaking 

Load. 

1 i 
d . ' 

l-S 

a 

Elastic 

Limit. 

Breaking 

Load. 

Elonga- 
; tion. 

Elastic 

Limit. 

__ 

Breaking 

Load. 

Elonga¬ 

tion. 

Hard Metal : 








' 



Charge No. 1197. 

i 

( n 635 


0 95 ^ ^ 

33 14 

1.20 

23.17 

49.84 

7.0 j 34.92 

73.66 

0.7 

“ “ 1204. 



U,y0 15.04 

35.56 

2.10 

18.66 

46.35 

7.5; 27.21 

70.80 

1.0 

“ “ 1211. 

0.55 

0.405 

1.05 16.06 

36 83 

4.0 

16.06 

46.35 

9.8 ‘ 18.28 

49 02 

6.5 

Medium M etal : 











Charge No. 1543. 

10 425 

0 275 

o 75 I 20 95 

36.76 

2.0 

22 09 

47.49 

12.21 23 .24 

47.75 

11.5 

“ “ 1558. 



, ! 19 81 

39.68 

3.3 

23.46 

46.29 

14 0 24.76 

48.76 

12.0 

“ “ 1565. 

0.45 

0.35 

1.101 19.55 

37.97 

2.8 

21.59 

46.99 

17.5 28.57 

53.97 

8.0 

Soft Metal: 











Charge No. 2078. 

, l o 26 

0 26 

0 12.23 

29.71 

12.8 

14.92 

31.24 

28.5 19.87 

35.87 

17.5 

“ “ 2262. 



y* 41 10.92 

30.35 

13 8 

12.19 

29.52 

26 5 19.74 

34.92 

22.8 

“ “ 18. 

; 0.317 

i 

0.30 

0.48 11.49 

1 1 

36.06 

14.8 

12.82 

34.41 

21.5 22.54 

42.98 

11.0 










































11 


OPERATION IN THE OPEN-HEARTH FURNACE. 


Tlie operation, as may have been gathered from the preced¬ 


ing pages, consists : 

1st. In the formation of an initial bath of 
pig to prevent oxidation during the process. 


manganiferous 


2d. In dissolving such sottening or decarburizing materials 
as wrought-iron in this bath. 

3d. In the addition, at the end of the operation, of silicon 
and manganese in such order and proportion as to prevent the 
formation ot blow-holes while casting, and at the same time 
give to the steel its special physical qualities. 

Another very important feature of the process is the method 
of taking tests. 


HARD STEEL. 

We will now describe in detail the different stages of the 
operation, and we will suppose at first, so as to avoid confu¬ 
sion, that the metal to be produced is of the harder kind. 

The Furnace .—The object of greatest importance during 
the whole of the operation is to keep oxidation as low as 
■possible in the bath. For this reason the furnace must, 
indeed, be kept as hot as possible, with a good solid body of 
flame; but there must be only just enough air admitted to 
promote thorough combustion. 

The Initial Bath ,.—This must be made of pig iron con¬ 
taining from 6 to S per cent, of manganese. Spiegeleisen is 
probably the most convenient form of pig; but, as a spiegel 
with this percentage may not be at hand at all times, the bath 
may be formed by taking a richer spiegel, sav 12 or 14 per 
cent, manganese, and diluting it with one-half ordinary pig 
containing no manganese. These mixtures can be made of 
any kind of spiegel or ferro-manganese. If we suppose, for 
instance, that the initial bath must be 600 lbs., and the only 
spiegel on hand is 18 per cent., by using 200 lbs. of it and 400 
lbs. of ordinary pig the bath will be brought down to its right 
point. 

In some cases the greater part of the bath should be made 


12 


of pig poor in carbon—as, for instance, when particularly 
highly carburized materials are to be dissolved in the bath. 

The weight of the initial bath, in proportion to that ot the 
whole charge, varies according to the conditions under which 
the heat is made. We may say, generally, that 11 per cent, of 
the whole is an average quantity. Every open-hearth melter 
knows that it is impossible to determine in advance the exact 
quantity of pig wanted for the operation. The temperature 
of the furnace has much to do with it. If it takes too long to 
melt the first charge, a great deal of the carbon will be carried 
away, and, in this case, it will be necessary to add pig at a 
later stage. The nature of the refining material has also a 
great influence. If a specially pure product is required, and 
the softening materials used are very tine puddled blooms 
nearly free from carbon and manganese, the initial bath must 
necessarily be larger, as well as richer in manganese; it may 
in this case reach 14 per cent, of the whole charge. 

The materials for the initial bath are always charged cold. 
The pigs are spread on the bottom, so as to hasten their melt¬ 
ing by exposing them to the direct action of the flame. At 
Terrenoire the first charge averages about 1,200 lbs., and is 
melted in an hour. 

When large pieces, like mould-fountains or ingot-ends, are 
to form part of the refining material, they are put in cold with 
the spiegel; they are placed on the bottom, and the spiegel is 
spread over them, so that it will melt first. This method, 
though accompanied by some oxidation, is thought economical 
in the long run, as these heavy pieces heat more quickly in 
the melting-furnace than in the auxiliary. It takes about 
four hours to melt a mixed charge of this kind weighing 
3,500 lbs. 

The Softening or Refining Materials .—Soon after the bath 
is completely melted the refining materials are successively 
added, in small lots of about 450 lbs. each. These are inva¬ 
riably pre-heated, as charging them cold and frequently would 
tend to keep down the temperature of the bath. When the 
initial bath consists of a small quantity of spiegel only, it is 
well to make the next charge small enough to be covered en- 


13 


tirely by the bath, in order to avoid oxidation. The materials 
must be dropped in front of the doors, at the deepest part of 
the hearth, and, if the pieces are covered by a thick film of 
oxide, it is well to shake or scrape it off before charging. 
The usual time for melting one of these lots is twenty 
minutes. Pre-heating is employed, not only to keep the fur¬ 
nace hot, but to save oxidation—to furnish an opportunity to re¬ 


move oxide before charging. The Terrenoire Company have 
never tried to melt the charge all at a time; they have feared 
that too long an exposure of the bare metal to the flame would 
oxidize it beyond redemption. The latest form of Pernot 
furnace, however, melts a 6-ton charge in three hours, the 
whole being charged at once and cold. This is even less time 
than required to melt an initial bath of 3,000 pounds at Terre¬ 
noire. 

The materials used in this second period of the operation 
are chosen with reference to the quality required in the 
finished product. They may be good Bessemer or open-hearth 
scrap, fountains from previous castings, puddled bars, or direct 
blooms. Materials inferior to these would correspondingly 
lower the quality of the product. For projectiles the Terre¬ 
noire Company generally nse Bessemer ingot and rail ends, 
with fountains from previous projectile charges. These are 
all pretty high in carbon and contain some manganese. This 
is the reason why such a comparatively small initial bath is 
required. The proportion of refining materials to the whole 
charge averages 78 per cent. 

As soon as a charge is melted another is added, and so on, 
until the operator thinks the time has come to assure himself 

of the state of the bath. A series of tests then commences. 

* 

Slag Tests before the Final Additions to the Bath .— 
Spiegeleisen is used for the initial bath, because the manganese 
it contains, being the most oxidizable of all the materials pre¬ 
sent, will remove oxygen that may be present in the bath, and* 
will intercept oxygen that tends to enter it. So that, the more 
manganese there is in the slag, the less oxygen there will be 
in the metal below, [f, then, the amount of manganese in 
the slag can be readily determined, there is constantly present 


14 


a delicate test of the oxidation of the bath. Oxide of iron 
tends to make the slag black ; manganese turns it light olive 
or ash-green ; and the different tints between these two ex¬ 
tremes give to the practised eye an exact idea of the state of 
the oxidation of the bath. 

To take a slag specimen, the workman thrusts into the fur¬ 
nace a flat iron bar (about 1^ by f in.), and, clearing away the 
top slag, moves it about in the under layer. The rod is quickly 
removed ; the slag is knocked off as soon as it sets, and is then 
allowed to cool. As the film is only from -A to ^ in. thick, 
this takes but a minute or two. The fracture of this film of 
slag reveals its color and texture. 

The manganese does not especially show in the slag during 
the first two or three hours of the operation, but its presence 
becomes noticeable by the rapid change which takes place after 
about a third of the scrap is charged. From black and porous 
the slag turns green and vitreous. At first the whole thickness 
of the specimen is of the same color, with the exception of the 
verv outside, which becomes oxidized by contact with the air. 
The fracture at that time resembles that of light olive-green 
glass; but this appearance soon changes as the oxidation goes 
on. The outside of the specimen, already oxidized in the fur¬ 
nace, shows a thicker film of black oxide, while the olive green 
of the inside deepens into a darker one. In most cases there 
appears on the inside—the side next the rod—a well-defined, 
light streak, with another darker one next to it, and, finally, 
the black outside streak. These shades do not die into one 
another, but stand side bv side in well-defined strata. As the 
additional materials are charged, the streaks grow darker and 
darker; the outside remains black, but the central part 
becomes brownish green, somewhat resembling dark bottle- 
green cloth, and the inside streak deepens into a dark pickled- 
olive green. Sometimes, and especially when nearly all the 
scrap is added, the fractured slag shows the dark bottle-green 
cloth color throughout. This is as deep as it should be allowed 
to go, as at this point very little of the manganese remains in 
the bath, and the safety of the operation is endangered. Even 
if the slag should become quite black—and this will happen 


15 


under some circumstances—the bath (‘an be saved by adding a 
small quantity of manganese, in the shape of a rich ferro¬ 
manganese ; 22 lbs. of 50-per-cent, ferro-manganese is a usual 
dose, and has generally the desired effect. Although the slag 
does not quite recover its greenish color, it becomes perceptibly 
lighter. It is only when the slag assumes a spongy, rotten ap¬ 
pearance that the bath may be said to be beyond redemption ; 
the oxidation is then such that it is impossible to determine 
the exact amount of silicon and manganese necessary to reduce 
it. But this is an exceedingly rare occurrence, and there is no 
record of its having happened since the regular manufacture 
of steel without blow-holes has been started. When it did 
happen during the experimental period, the bath was treated, 
as in the ordinary Martin operation, by the addition of spiegel 
or ferro-manganese, and ordinary ingot-steel was made. This 
can always be done in case of any mishap. 

Hammering and Coldd)ending Tests before the Final Ad¬ 
ditions .—The slag test gives no indication of the physical 
state of the metal, which is an equally important guide in the 
operation. When, therefore, the operator has reason to 
believe that the metal is approaching the point of sufficient 
softening or purification, he makes the following tests: A 
ladleful of metal is taken from the furnace and cast into a 
round ingot about 3 in. in diameter and l 1 / in. thick. The 

ino-ot is knocked out of the mould as soon as set, and flattened 

& 

under a special steam-hammer, at its original heat, into a disk 
about 6 in. in diameter and in. thick. 

This method of taking tests has many advantages which 
recommend it to all practical steel-makers. It gives an excel¬ 
lent opportunity to judge of red-shortness, and the test-piece 
is of sufficient size for cold-bending. The system is rapid, 
convenient, and accurate, and it furnishes a comparative scale 
much safer than the mere fracture of a very small ingot. 

No tests are taken until all but two or three ot the softening- 
charges have been added. The flattened disk at this stage of 
the operation shows starred edges, and sometimes deep radial 
cracks iy 2 to 2 inches deep. 

All test disks are prepared for cold-bending by being cooled 


16 


in the air three or four minutes, till they are black-hot, and 
then completely cooled in soap-water. The disk is bent to 
show its softness; if taken before the last charge but one, it 
will usually bend about \]/ 2 in., and break. One taken before 
the last charge would show little improvement in the hammer¬ 
ing, but would bend to an angle of 45°. A test taken alter 
the last charge would hammer about like the others, but it 
would bend until the folds were y 2 or in. apart, and, if 
doubled up flat under the steam-hammer, would crack clear 
across, yet without breaking off. 

It happens sometimes that a charge threatens to become too 
soft; the test taken before the last two charges may bend a 
little too much, showing too great decarburization. The 
remedy is the same as in the ordinary Martin practice, and 
consists in adding spiegel—the amount, of course, cannot be 
definitely stated ; it is determined by an expert examination 
of the tests. 

If, on the other hand, the tests prove too hard, an additional 
charge of softening material should be made. Puddled blooms 
might be substituted for steel scrap, if the latter had formed 
the charge. 

After the last softening charge has been added (in case the 
finished product is to contain about 0.55 carbon) the test ingot, 
hammered to a ^-in. thick disk, should have a number of small 
cracks, from l /% to y in. deep, all around the edges, and per¬ 
haps two or three deep radial cracks from 1 to 2 in. deep; it 
should bend withont breaking until the folds are from ]/ 2 to 
1 in. apart, and, when brought to a close fold under the steam- 
hammer, a crack should be seen clear across the bend. Any 
verv great deviation from this result will announce a disturb- 
ance in the bath, and suitable steps to remedy it should be 
taken at once. 

It often happens that the metal tests prove soft enough 
when the slag is vet very light. This occurs, in a thoroughly 
well-going furnace, when the oxidizing influence of the flame 
is reduced to a minimum. The manganese burns slowly, and 
is insufficiently removed when the carbon has been brought 
down to the right point bv the.relining materials. In this 


17 


case the amount of manganese introduced with the final addi¬ 
tions is reduced in a manner proportionate to the color of the 
slag. The same result might be obtained by leaving the 
charge in the furnace long enough for the manganese to burn 
away ; but some of the carbon might also escape and make the 
metal too soft, which defect could be remedied only by a 
further addition of spiegel, causing expense and loss of time. 

It. will be seen that by means of the tests above described 
the operator can judge of the state of his metal with great 
nicety, and lias at hand all the necessary elements to remedy 
any unfavorable tendency likely to develop during the opera¬ 
tion. 

When satisfactory tests have been obtained, after all the 
above-mentioned materials have been charged, the operation is 
allowed to go on undisturbed for some time, so that the bath 
may store up heat enough to ensure thorough fluidity while 
casting, as well as a rapid incorporation of the ingredients in¬ 
troduced with the final additions. It is during this heating 
period that the. slag tests become specially important. The 
aim is to burn away as much manganese as possible without 
oxidizing; anv iron. The manganese in the original bath is to 
be consumed, in order that the definite quantity of this mate¬ 
rial added just before casting may do its definite work; and 
yet it must not be quite consumed until the moment of the 
final additions, otherwise the bath will become oxidized. 
When the furnace is very hot, and the slag has reached the 
proper color—which varies between a dark pickled-olive green 
and a darker greenish brown—the bath is in a condition to 
receive the final additions. 

The final additions .—These consist of a special pig, con¬ 
taining both silicon and manganese, and also an additional 
quantity of manganese introduced in the shape of a 50 or 60 
per cent. Mil. ferro-manganese. A part of these ingredients 
is taken up by reactions which prevent the formation of blow¬ 
holes ; the remainder is left in the metal to impart to it the 
physical qualities shown in Table A. The usual charge con¬ 
sists of 11 per cent, of special pig, having the following com¬ 
position : 


18 


Mn . 3.50 

C. 3.00 

Si. 4.20 to 4.60 

P. 0.10 

If the special pig contains less than 4.50 of silicon, 12 per 
cent, should be added. Ferro-manganese also is employed, 
because the special pig, as at present made in the blast-furnace, 
does not contain enough manganese. The proportion of 50 to 
60 per cent. Mn. ferro-manganese used varies from 1 to 1.3 
per cent, of the total charge. In particular cases the amount 
must be decreased—as, for instance, when the slag is greener 
than usual before the final additions; expert practice must be 
the guide in this case. 

The special pig is charged hot. While it is melting a 
marked change takes place: the bath, which up to that time 
had bubbled about as much as in the ordinary pig and scrap 
operation, becomes gradually more and more quiet, until its 
surface is smooth and scarcely broken by small and widely- 
scattered bubbles. When the special pig is nearly all melted 
the ferro-manganese is thrown in hot. The bath is then 
rabbled vigorously for about a minute, and casting takes place 
immediately. 

Final metal tests .—While casting is going on a few more 
tests are taken, so as to get a definite idea of the quality of 
the finished product. The test ingot is hammered just as soon 
as it comes out of the mould, without reheating. The result¬ 
ing disk has smooth, rounded edges, but is, of course, much 
harder than the previous disks. After having been allowed to 
cool in the air, the disk is placed flat on a hollowed block, so 
that the edges only bear. It is then struck in the centre with 
a 20-lb. sledge swung clear around. Three test disks are 
generally broken at the end of each charge, and the average 
number of blows gives a pretty good idea of the quality of the 
metal. Four blows arc considered a good average, and the 
permanent bend should not be more than ^ inch ; less bend¬ 
ing proves the material too brittle; more bending proves it 
too soft. 

These final tests might, at first sight, appear unnecessary ; 






19 


the metal is cast and nothing can change its nature in the 
moulds. While this is true of ordinary steel, it must be re¬ 
membered that this metal has to be annealed before it is used. 
If, therefore, the final test pieces show a deviation from the 
accepted average, all castings belonging to that charge are 
followed to the annealing-furnace and heated a shorter or 
longer time, according to the characteristics developed by their 
tests. 

In addition to the breaking of these disks, a test ingot is 
usuall} r broken under the steam-hammer. It is placed on a 
short piece of double-headed rail resting on the anvil; a piece 
of 24-in. square steel is laid upon it and the hammer is dropped 
at full stroke. This is a check on the disk test, and it also 
shows the fracture very well. 

In practice, the test ingots are never reheated. It might, 
in particular cases, become necessary to do so, but the know¬ 
ledge thus derived adds very little to what can be learned from 
a direct test. We did reheat and hammer some ingots; be¬ 
fore the final additions the disks cracked less on the edges and 
bent a little better; the final tests seemed a little more ductile, 
but the malleability was not improved. 

In general it may be stated that this steel is not improved 
by hammering, nor is it injured ; it may often be important 
to draw down some parts of a casting. 

Casting .—At Terrenoire, in the old shop where this manu¬ 
facture is carried on, the metal is tapped directly from the 
furnace into the moulds. There are two tap-holes, side by 
side, running into one spout fitted with two nozzles. If one 
of the holes gets stopped the other is opened (see my Report 
No. 8, page 28, First Series). The moulds stand on a truck 
moved by a windlass at each end of a long trench-like casting- 
pit directly in front of the furnace. It is useless to state that 
this is a very objectionable way of casting. It never takes 
less than fifteen minutes to run a charge out of the furnace 
when everything goes smoothly, while, under the most favor- 
able circumstances, the steel running between the moulds as 
they are brought successively under the nozzle makes a great 
deal of scrap. But despite these disadvantages the manufac- 

% 


20 


ture has been going on for several years without serious acci¬ 
dent. This is probably due to the perfect quietness of the 
metal; it runs into the moulds without any splashing, and no 
escape of gas is noticed during the whole casting operation. 
The steel settles dead and level in the fountains, and the 
covers, laid loosely on the sand which is thrown upon the 
metal, are never disturbed. It is evident, however, that this 
special steel is not quite as fluid as ordinary steel having the 
same percentage of carbon. This is due to the presence of 
silicon. Hence, as before mentioned, a very hot furnace is 
indispensable. 

SOFT STEEL. 

The composition of the charge and the nature of the tests 
in the manufacture of soft steel differ in some essential points 
from the description above given. 

The Initial Bath .—As the additional materials for a soft 
charge are poorer in carbon than those for a hard one, 
an equal amount of the former will refine a larger amount of 
pig. For this reason the weight of the initial bath is 14 per 
cent, of the total charge, instead of 11 per cent. These 
materials, unlike Bessemer rail-ends and fountains, contain 
little or no manganese ; it becomes, therefore, necessary to 
increase the proportion of this ingredient in the bath, so as to 
keep the slag good to the end. Experience has proved that a 
12 per cent, spiegel will accomplish this object. The bath 
may be made in various ways, and of different mixtures, as 
described for hard steel, so that the proportion of manganese 
is kept right. 

The furnace should be kept, if anything, hotter than for 
hard steel, because, the proportion of carbon being reduced, 
the metal, while casting, will otherwise be less fluid, and will 
tend to chill in the nozzle and tap-hole. When the pig is all 
melted, it is well to wait a few minutes before adding anything 
more, so as to get the bath as hot as possible. 

The Refining Materials .—These must consist of highly 
decarburized iron, and should be as free as possible from 
phosphorus. Blooms puddled from good Bessemer pig are 


/* 


t 


21 


generally used, and occasionally soft-steel scrap of fine quality. 
These materials are pre-heated to a bright red and charged in 
lots ot about 450 lbs. They are well shaken and scraped 
before being put into the bath, so as to remove the oxide with 
which thev are coated. As soon as a charge is melted another 
is added, and so on until all but two or three are in. A set 
of tests is then made. Puddled blooms are a little harder to 
melt than rail-ends. It usually takes a full half-hour to 
thoroughly melt a 450-lb. charge. The blooms must be 
dropped in the middle of the furnace, at the deepest part of the 
bath, so as to be covered by it. 

Tests before the final additions .—Both slag and metal 
tests are taken in the manner before described. The slag 
fractures should not varv much from those for hard steel, 
except that they may be a shade darker. Since the pro¬ 
duct must be purer, and poorer in carbon, 1 manganese, and 
silicon, these substances should be pretty well eliminated 
before the final additions are made, provided, however, that 
oxidation is not allowed in the bath. A black slag, although 
vitreous and clear, would require the addition of ferro-manga- 
nese; but if the slag is yet too light after blooms enough are 
put in to bring the charge to the desired weight, the bath 
must be left undisturbed until the color has reached the proper 
shade. 

The hammered disks should be somewhat smoother and 
much softer than hard-steel test pieces. Usually the edges are 
rough and serrated, but the large radial cracks are fewer and 
shallower. In appearance the soft-steel disks are intermediate 
between the hard-steel disks before the addition of special pig 
and the corresponding finished steel disks. The metal has 
reached the right point when the forged disk bends to a close 
fold under the steam-hammer without cracking at the back of 
the bend. For very soft metal these disks should double up 
again to a four-fold piece with a little cracking in the centre. 
The metal tests previously described, and those just above 
mentioned, may be taken as the extreme limits of the scale 
between which all degrees of hardness have as yet been pro¬ 
duced. 


22 


\ 


If the tests prove the metal too soft, spiegel is added; if too 
hard, after the full weight is charged (and this, as before 
stated, happens in connection with a light slag), the manganese 
and carbon are given time to burn away before the addition of 
special pig. 

It is well at any rate to give the bath time to get hot at this 
period, and the final additions should be made only when the 
slag threatens to become too dark. 

The final additions .—These consist of a special pig of the 
following composition: 


C. 1.60 

Mn. 14.00 

Si. 7.50 

P. 0.125 


Such a pig is made and used at Terrenoire, but a pig con¬ 
taining the indicated proportion of silicon and no manganese 
could be substituted, the proper amount of the latter ingredi 
ent being introduced in the shape of a very rich ferro-manga¬ 
nese—the only difficulty is the greater addition of carbon by 
this method. 

The usual proportion of this special pig is 3to 4 percent, 
of the charge already introduced, depending somewhat on the 
percentage of manganese required in the product and on the 
appearance of the slag. In general, there should be about 0.80 
per cent, of manganese introduced, in order to leave about 
0.60 per cent, in the finished product. When as high a per¬ 
centage as this is wanted, it is necessary to make a still further 
addition of ferro-manganese, which must be rich, say not less 
than 75 per cent. Mn. When a low percentage of manganese 
is required in the finished product—0.40 and below, for in¬ 
stance—that introduced with the special pig is sufficient. 

The special pig is pre-heated to a bright red and charged 
when the bath is very hot. If ferro-manganese is used in ad¬ 
dition, it is thrown in when the pig is nearly all melted. The 
furnace-man feels with his rabble to make sure that everything 
is melted; lie then stirs the bath vigorously for about a 
minute, and casting takes place immediately. 

Casting is done as described above. The steel is not very 


I 






23 


fluid. It gathers a little around the nozzle, and the solidified 
particles must be removed by a carefully-handled bar, in order 
to prevent the closing of the hole; but with this precaution 
there is little difficultv. The use of a ladle would allow more 

t/ 

rapid casting, and so largely avoid chilling. 

Tests while casting .—These are taken exactly as described 
above, but they show a much softer material. When ham- 
mered they look very much like hard-steel tests, but, instead 
of breaking with a few blows, they bend without cracking 
until the folds are ^ inch apart, and when brought together 
under the steam-hammer a wide crack will show clear 
across the disk, although the pieces will not fall apart. The 
metal shows a much coarser grain than hard steel. When a 
test ingot is broken whole under the hammer, as described 
above, it requires three times as many blows to start- a crack, 
and additional pounding to tear the pieces apart The fracture 
in this case shows a strong-grained metal, the ductility of 
which is proved by the marked deformation it bears before 
breaking. 

ILLUSTRATIONS OF THE PRACTICE. 

In order to give the steel-maker a still better idea of the 
practice, we will now describe several operations which we 
witnessed at Terrenoire in the early part of 1877. 

Charge 127, February 27. 

In this charge no disturbance of normal conditions occurred. 
The times of charging and test were as follows : 

At 7.10 a.m. initial bath, 1,320 lbs. 7 per cent. Mn. spiegel. 

At 7.10 a.m. “ 2,178 lbs. fountains from previous heats. 
The fountains were charged first and well spread on the 
bottom. The spiegel was placed upon the fountains, the whole 
being cold. The furnace being very hot, the spiegel was melted 
at 8.30; but the fountains melted much more slowly, and not 
until 11.05 was the whole charge fluid. . 

At 11.20, 440 lbs. of Bessemer rail-ends were charged at a 
bright-red heat, care being taken to shake off the oxide adher¬ 
ing to them. 

At 11.40, 440 lbs. Bessemer rail-ends charged. 


24 


At 11.55, 440 lbs. Bessemer rail-ends charged. 

At 12.15, 448 lbs. Bessemer rail-ends charged. 

At 12.80 a preliminary slag test was taken. The fracture 
showed a liglit-green color interwoven with darker streaks; 
it somewhat resembled certain varieties of malachite. 

At 12.37, 440 lbs. rail-ends charged. . 

At 1.00, 448 lbs. rail-ends charged. 

At 1.15, 440 lbs. rail-ends charged. 

At 1.20 a second examination of the slag showed it much 
darker than the first test. The outside film was quite black; 
the streak nearest the rabble was yet light, while the inter¬ 
vening space had deepened to a pickled-olive green. 

At 1.40, 440 lbs. rail-ends charged. 

At 2.00, 440 lbs. rail-ends charged. 

At 2.20, 440 lbs. rail-ends charged. 

At 2.30 the first steel test was taken. The edges cracked 
considerably all around ; there were four large cracks ranging 
from y to iy in. deep. The disk bent to an angle of 60° and 
broke. The fracture showed a very fine-grained, steely metal. 
The slao- test taken in connection with this metal test was 

O 

much darker than the preceding one. The light streak had 
disappeared, and the black outside film was a little thicker 
than before. It was decided that the bath would bear another 
charge of rail-ends. 

At 2.40, 440 lbs. of rail-ends charged. 

At 2.50 a second steel test was taken. The edges of the 
disk were less rough, and three large cracks only were seen, one 
of them being about iy in. deep. The disk bent until the 
folds were within y inch apart, and when hammered flat 
cracked clear across, but the pieces hung together. This was 
considered a good test. The slag specimen taken in connec¬ 
tion was very nearly the same as the previous one. The bath 
was allowed to heat for some time. 

At 3.00 a slag test was taken ; the fracture was clean and 
vitreous, and the color gradually shaded from black on the 
outside to pickled-olive green on the inside. It was thought 
that the oxidation had reached the limit. 

At 3.07, 910 lbs. of special pig were added at a bright-red 


25 


heat. This was very nearly eleven per cent, of the charge 
already in the furnace. At 3.15 it was ascertained by feeling 
with a rabble that the pig was very nearly melted. It is well 
known that when scrap or ordinary pig are thrown into an open- 
hearth bath, there is a continual bubbling immediately above the 
place where they are placed. No such phenomenon occurs with 
this special pig ; on the contrary, during the whole previous part 
of the operation the bath bubbles about as much as in any pig 
and scrap charge when good materials are used, but as soon as 
the silieious pig begins to melt, this bubbling gradually ceases, 
until, at the end of the operation, the bath is quite still and 
smooth. 

At 3.17, 139 lbs. of 50 per cent. Mn. ferro-manganese were 
charged hot. The bath was immediately rabbled, so as to aid 
the mixing and reactions. 

At 3.20 casting took place. While casting was going on, 
three test ingots were taken ; two were hammered to disks 
which broke respectively at 7 and 2 blows of the sledge ; the 
third ingot broke at 2 blows (the usual number) of the steam- 
hammer, thus showing a very good average. 

The time occupied in melting the charge was 8 hours 10 
minutes, which is about the average. 

The composition of the charge was as follows: 

7 $ Mn. Spiegel. 1,320 lbs., or 14$ of the whole charge. 

Refining materials. 7,034 lbs., or 74.8$ 

Special pig. 910 lbs., or 9.8$“ 

Ferro manganese, 50$ Mn. 139 lbs., or 1.4$ 

Total. 9,403 lbs. 100$ 

The proportions of the different ingredients introduced by 

the final additions are : 

Carbon in special pig.27.3 lbs. ) or q 42 $ 

“ in ferro-manganese 7.64 lbs. f 

Silicon.41-86 lbs., or 0.50$ 

Manganese in special pig 31.85 lbs. 1 or ^ 2 2$ 

“ in ferro-mang. 70. lbs. ) 

The percentages given above are in relation to the amount 

charged before the final additions. 

The quantity of carbon left in the bath befoie the final 
addition amounted probably to 0.30 or 0.35 per cent.; the 










26 


quantity of silicon was reduced very nearly to nothing, and 

the manganese was below 0.15; so that, after the reactions 

had taken place, the final product would retain a chemical 

composition similar to that of the hard metal in Table A. 

The whole charge was cast into projectiles for the French 

navy. 

•/ 

Charge 1 23, February 20. 

This charge was a little irregular in its behavior. 

At 9.30 a.m. initial bath, S80 lbs. 7 per cent. Mn. spiegel. 

u u 2,2SS lbs. steel fountains. 

Both were charged cold, the fountains being spread on the 
bottom and the spiegel on top. 

The furnace worked rather slowly for the first hour, but 
gradually improved, until it got into first-rate condition, with 
a solid body of non-oxidizing flame. 

At 1 o’clock 440 lbs. of Bessemer rail-ends were well 
cleaned of oxide and charged at a bright-red heat. 

At 1.20, 440 lbs. of Bessemer rail-ends were charged. 

At 1.45,440 lbs. “ “ “ 

At 2.05,410 lbs. “ “ “ 

At 2.30,440 lbs. “ “ 

At 2.45,440 lbs. “ “ “ 

At 3.05,440 lbs. “ “ “ 

At 3.15 the first slag test was very light green throughout. 
At 3.20, 440 lbs. of Bessemer rail-ends were charged. 

At 3.45,440 lbs. “ “ “ 

At 4.10,451 lbs. “ “ t “ 

At 4.25 the slag was yet light, differing only from the pre¬ 
vious specimen in having a few dark streaks. 

At 4.30, 448 lbs. of Bessemer rail-ends were charged. 

At 4.50,440 lbs. “ “ “ 

At 5.15 the first test ingot hammered into a much cleaner 
disk than usual; the edges were tolerably smooth, and there 
were only two noticeable cracks, the deepest about yi inch; 
but it broke after about 1% inch deflection. The correspond¬ 
ing slag test was light yet, though a little darker than the 
others. The presence of much manganese in the bath explains 
the better hammering of the test ingot. The metal was 


27 


certainly too hard, and, as it was necessary to limit the charge 
to a certain weight, it was decided to use puddled blooms 
instead ot rail-ends, in order to bring it down more rapidly. 
It seemed as if the furnace had no tendency to oxidize, and 
that refining took place by dilution only. 

At 5.35, 253 lbs. of puddled blooms were charged. 

At 6.10 a metal test hammered well, and, although a little 
hard, it bent double with the usual crack clear across, but 
without breaking apart. The corresponding slag test was, 
like the 5.15 test, very light, the black film having hardly 
appreciable thickness. But, as the metal was good, it was de¬ 
cided to introduce the final additions and decrease the quantity 
ol manganese in a manner corresponding to the color of the 
slag. 

At 6.35, 968 lbs. of special pig, representing about 11 per 
cent, ot the weight already charged, were introduced, at a 
bright-red heat. 

At 6.37, when this pig was almost or quite melted, 106 lbs. 
of 50 per cent. Mn. ferro-manganese were charged hot. The 
bath was then thoroughly rabbled, and casting took place at 6.40 
p.m. Three test ingots, taken while casting, were hammered 
into disks and broken cold respectively with 8, 7, and 2 blows 
of the hammer. 

The time of the heat was 9 hours 10 minutes. 

The whole charge was as follows: 


7# Mn. spiegel. 880 lbs., or 9.4 per cent, of the whole charge. 

Refining materials. 7,440 lbs., or 79.2 “ “ “ 

Special pig. 968 lbs., or 10.3 “ “ “ 


50#Mn. ferro-manganese.. 106 lbs., or 1.1 


Total. 9,394 lbs. 100.00 

The quantity of the different ingredients introduced with 

the final additions, and their proportions in relation to the 

amount previously charged, were as follows: 

Carbon in special pig. 29.04 lbs., 1 0 4Q 

“ ferro-manganese. 5.83 lbs., f F 

Silicon.. 44.52 lbs., or 0.51 

Manganese in special pig.. 33.88 lbs., ) n QQ ,< 

“ ferro-manganese. 53.00 lbs., } 


These pioportions were much the same as in the previous 
charge, excepting that less manganese was put in, an unusually 













28 


large amount of it having remained in the bath before the 
final additions. Of course no rigid rule for such additions 
can be given ; practice soon becomes a reliable guide. In 
this case the operator did not miss the mark, as the tests 
stood the average number of blows. 

V. J 

The whole charge went into one casting—a brace for a large 
gun-carriage. The pattern was rather intricate, with thin 
ribs and cores hard to hold; but the piece came out quite as 
good as any ordinary cast-iron casting. It was considered a 
success, and a number of similar castings were to be made for 
the French Government. 

Charge 122, February 20. 

At 6.30 a.m. initial bath, 1,100 lbs. 7 per. cent. Mn. spiegel. 
“ “ 1,100 lbs. fountains. 

u “ 1,100 lbs. Bessemer ingot-ends. 

All charged at a time, cold, the fountains and ingot-ends on 
the bottom and the spiegel on top. 

At 10.35 this charge was apparently melted. 

At 11.00, 440 lbs. Bessemer rail-ends were charged. 

At 11.15,440 lbs. “ “ “ 

At 11.35,440 lbs. “ “ 

At 12.00,440 lbs. “ “ 

At 12.20,440 lbs. “ “ “ 

At 12.45,440 lbs. “ “ 

At 1.10, 440 lbs. “ 

At 1.20 the slag was found to be rather dark, with a well- 
defined black film on the outside. 

At 1.25 the first test-disk showed the usual rough edges and 
three deep cracks, but it bent to a close fold with very little 
cracking. The metal was judged too soft. 

At 1.40, 220 lbs. of 7 per cent. Mn. spiegel were charged, 
in order to restore the proper amount of carbon to the bath ; 
it was placed cold on the banks, where it gradually melted. 
This should always be done; if spiegel is dropped in the mid¬ 
dle of the bath, it will adhere to the bottom and raise some 
parts of it to the surface while melting. 

At 2.05, 440 lbs. Bessemer rail-ends were charged. 


29 


At 2.30, 440 lbs. Bessemer rail-ends were charged. 

At 2.45 a test-disk resembled tlie first one, but when bent 
double under the steam-hammer it cracked nearly clear across. 
The corresponding slag was about like the other, excepting 
that the inside next to the rod was somewhat lighter. These 
tests were considered right, and the bath was given time to 
heat. 

At 2.55 a slag specimen did not differ essentially from the 
2.45 test. 

At 3.00, 822 lbs. of special pig were charged—about 11 per 
cent, of the charge already in the furnace. 

At 3.08, the pig being very nearly melted, 125 lbs 4 *of ferro¬ 
manganese were thrown in hot. The bath was rabbled, and 
at 3.10 casting took place. 

Two tests, taken while casting, broke with 8 and 5 blows; 
a whole test-ingot broke under the steam-hammer at the third 
blow. 

The time occupied by the operation was 8 hours 40 
minutes. 

The whole charge was as follows: 

i$ spiegel. 1,320 lbs., or 15.7$ of the whole charge. 

Refining materials. 6,100 lbs., or 73.1$ “ “ “ 

Special pig. 822 lbs., or 9.8$ “ “ “ 

Ferro-manganese. 125 lbs., or 1.4$ “ “ “ 

8,427 lbs. 100.00$ 

The following table shows the quantity of the different 
ingredients introduced with the final additions, and their pro¬ 
portion to the charge as it stood before these additions: 

Carbon in special pig. 24.66 lbs., ) n 

“ in ferro-manganese. 6.87 lbs., ) ' 

Silicon. 37.81 lbs , or 0.50$. 

Manganese in special pig. 28.77 lbs., ) 1 

“ in ferro-manganese. 62.50 lbs., f ‘ 

The charge was used in casting projectiles for the French 
navy. 

Charge 116, February 19. 

At 3.20 a.m. initial bath, 1,100 lbs. 7 per cent. Mn. spiegel. 

“ “ 2,222 lbs. fountains. 












30 


At 6.45 the whole charge was melted. 

At 7.10, 444 lbs. Bessemer rail-ends were charged. 

At 7.30, 440 lbs. “ “ 

At 7.50, 451 lbs. “ “ 

At 8.10, 440 lbs. “ “ 

At 8.25, 440 lbs. “ “ “ 

At 8.50, 440 lbs. “ “ “ 

At 9.10, 440 lbs. “ “ “ 

At 9.30, 440 lbs. “ 

At 9.45 the first metal test had the usual appearance, but 
broke before bending to a close fold. It was judged too hard. 
The corresponding slag test was a little darker than it should 
have been. 

At 9.50, 440 lbs. of Bessemer rail-ends were charged. 

At 10.10, 440 lbs. “ “ 

At 10.30, 440 lbs. “ “ “ 

At 10.45 a second test-disk had very rough edges, and there 
were four well-defined, deep cracks. The disk bent to a close 
fold, but the crack at the back did not reach half way across. 
These signs proved the bath to be oxidized, and upon examining 
the slag it was found to be completely black, but vitreous and 
clear. It was therefore necessary to add manganese in order 
to reduce the oxide of iron and bring the bath to a point where 
the final additions could fulfil their proper functions; 22 lbs. 
of 50 per cent. Mn. ferro-manganese were thrown in cold, 
introducing 11 lbs. of metallic manganese, which is the pro¬ 
portion generally used in such cases. 

At 11.00 another slag test showed the very dark greenish 
brown color inside with a black streak outside. No more metal 
tests were taken. 

At 11.06, 895 lbs. of special pig were charged, or about 11 
per cent, of the amount previously charged. 

At 11.17 the pig was nearly all melted, and 136 lbs. of 50 
per cent. Mn. ferro-manganese were thrown in hot. The bath 
was vigorously rabbled, and at 11.20 casting took place. 

The final tests stood respectively 6, 11, and 20 blows of the 
hammer before breaking; but the permanent bend was in no 
case more than half an inch. The metal was judged hard 


31 


enough for projectiles, as its tendency to softness was not so 
strong that it could not be remedied by annealing at the pro¬ 
per temperature. 

The time of the charge was 11 hours, and the composition 
was as follows: 

7% spiegel. 1,100 lbs., or 11.9$ of the whole charge. 

Refining materials. 7,075 lbs., or 76.9$ “ “ “ 

Special pig. 895 lbs., or 9.7$ “ “ “ 

50$ ferro-manganese. 136 lbs., or 1.5$ “ “ “ 


®:48 lbs.;} 


9,206 lbs. 100.00$ 

The final additions introduced the various ingredients in the 

following quantities and proportions: 

Carbon in special pig. 26.85 lbs., 

“ in ferro-manganese. 7.48 lbs., 

Silicon. 41.17 lbs.,' or0.50$. 

Manganese in special pig. 31.32 lbs., ) . 91(f 

“ in ferro-manganese. 68.00 lbs., \ ' /o% 

All the above charges represent the hardest type of steel 

likely to be used in castings. 

Soft-Steel Charge 157, February 27. 

At 8.20 a.m. initial bath, 1,100 lbs. of 12 per cent. Mn. 
spiegel. 

This was charged cold and well spread on the bottom. 

At 9.30, 471 lbs. of puddled blooms were charged hot. 

At 9.55, 440 “ “ “ 


u 


u 


u 


a 


u 


u 


u 


u 


u 


u 


a 


« 


u 


u 


a 


u 


a 


u 


ki 


a 


C 4 


u 


At 10.25, 471 
At 11.00, 471 
At 11.35, 440 “ 

At 12.10, 471 “ 

At 12.45, 440 “ 

At 1.15, 471 u 
At 1.55, 440 a 
At 2.15 the first test-disk showed a tolerably good edge 
and three radial cracks about if inch deep. When bent to a 
close fold under the steam-hammer, it cracked half way across; 
the grain was very much coarser than that of the hard-steel 
tests. The metal was thought too hard. The corresponding 
slag test was beginning to deepen in color, and had a decided 
black streak through the centre. 













32 


At 2.25, 471 lbs. of puddled blooms were charged. 

At 2.45, 471 “ “ “ “ 

At 3.00 a second metal disk looked very much like the 
first, but it bent to a close fold without cracking in the least ; 
and it even bent fourfold without tearing apart, but there 
was a deep crack in the centre. The grain was strong, and 
the fracture was torn and not short. The metal was now 
judged soft enough. The corresponding slag test was darker 
than the first, with a black streak running yi of the thickness 
of the specimen. 

At 3.30 another slag test was very dark, with thin, lighter 
lines running through it. 

At 3.42, 220 lbs. of the special pig for soft steel were added. 
This was about 3 ]/ 2 per cent, of the charge already in the 
furnace. As it was not necessary to have a large proportion 
of manganese in the finished product, no ferro-manganese was 
added, and, after the bath had been thoroughly rabbled, cast- 
ing took place at 3.50. 

The final tests hammered into perfect disks, which bent with¬ 
out cracking until the folds were about half an inch apart. 
When brought to a close fold under the steam-hammer, they 
cracked clear across without breaking asunder. It required 8 
blows of the steam-hammer to start the test ingot, and, 
although it cracked in three places, the pieces hung together 
so that it was impossible to tear them apart by hand. 

The time of the charge was 7 hours 30 min., and its com¬ 


position w r as : 

12# spiegel.1,100 lbs., or 17.2# of the whole charge. 

Refining material.5,057 lbs., or 79.4 “ “ “ 

Special pig. 220 lbs., or 3.4 “ “ “ 


6,377 100.00 

The special pig introduced the different ingredients in the 
following quantities and proportions : 


Carbon. 3.52 lbs., or 0.057# 

Silicon..16.50 lbs., or 0.267# 

Manganese... .30.80 lbs., or 0.500# 


There probably remained, in the bath just before charging 
the special pig between 0.15 and 0.20 of carbon, hardly any 










33 


silicon, and not more than 0.15 of manganese. After the 
reaction had taken place, the finished product would probably 
have shown a chemical composition similar to that of the soft 
steel in the large appended table. 

In this charge only 3 ]/ 2 per cent, of special pig was used, 
and no ferro-manganese, in order to obtain the softest metal 
possible. If a harder shade is desired, four per cent, of 
special pig should be used; and an amount of ferro-manganese 
depending upon the degree of toughness required in the 
finished product. It is obviously possible and easy, by vary¬ 
ing the proportion of the ingredients, to change the qualities 
of the metal; but care should be taken lest too much silicon 
remains in the bath ; 0.40 per cent, seems to be a limit—a 
larger quantity would tend to decrease the ductility arid elas¬ 
ticity of the product. The large appended table, in which a 
number of charges are noted in detail—their composition, 
analyses, and physical tests—clearly shows what the final addi¬ 
tions should be for each kind of product. 

OPERATION IN THE BESSEMER CONVERTER. 

This manufacture of steel without blow-holes has never 
been tried in the Bessemer converter, but a method is indicated 
by which it could undoubtedly be successfully carried on. The 
use of iron very highly charged with manganese would cause 
an objectionably high temperature and much slopping; the 
amount of manganese must, therefore, be so regulated that a 
practicable quantity of scrap or blooms thrown into the con¬ 
verter during the blow will keep down the heat. At the same 
time there must be manganese enough present to furnish food 
for the oxygen, so that little or no oxide of iron shall remain 
in the bath when the time comes for the final additions. Tests 
as above described would be taken from time to time by turn¬ 
ing down the' converter; when they were right the special 
pig and the ferro-manganese would be put into the ladle, hot 
or in a melted state, just before the contents of the converter 
were emptied in. The charge would thus get a thorough 
stirring, equivalent to the rabbling in the open-hearth opera¬ 
tion. 


34 


Many suggestions regarding the operation in the Bessemer 
converter will occur to the expert, and it is probable that 
careful trials, accompanied bv complete analyses, would enable 
a skilful operator to work successfully, especially in the pro¬ 
duction of hard steels. 

OPERATION IN CRUCIBLES. 

This has not been tried as yet, but it is difficult to see why 
it should not be successfully performed. The main objection 
to the crucible practice is its costliness. It would certainly 
demand less care and watching than the open-hearth opera¬ 
tion. When the crucibles are charged and covered, the metal 
is out of the reach of oxidation, and by pouring the final 
additions into the ladle just before teeming, a thorough incor¬ 
poration would be secured. The facility with which the com¬ 
position of the charge could be varied in the crucible would 
be very important in some cases, when, for instance, a metal 
containing an extreme quantity of carbon or of manganese was 
wanted; these ingredients could be initially charged in definite 
proportion without fear of further disturbance during the 
operation. But, from an economical standpoint, the open- 
hearth process seems to offer advantages over all others for 
the manufacture of sound steel castings. 

THEORY OF THE PROCESS. 

We are now prepared to review the chemical reactions which 
take place at different periods of the operation. It has recently 
become well known that blow-holes in steel ingots are filled 
vrith carbonic oxide produced by the reaction of oxide of iron 
on the carbon, according to the formula : 

Fe 3 0 4 +C=3Fe0+C0. 

Durirg the cooling period the solubility of the carbonic 
oxide diffused through the metal rapidly diminishes, and some 
gas-bubbles remain imprisoned in the solidified mass. The 
problem is, therefore, how shall the production of carbonic 
oxide be prevented just previous to casting? This problem 
seemed, as mentioned above, to have been solved by some 


85 


English and German manufacturers —Krupp among others— 
who for the past ten or fifteen years have exhibited large, 
sound ingots weighing up to 45 tons. An analysis of these 
steels shows them to be highly carburized and siliconized; 
they contained sometimes as high as 0.40 per cent, of the latter 
ingredient. To find an explanation of this result it is neces¬ 
sary to go back to the theory of the Bessemer process. It is 
well known that during the first period of the operation the 
combustion of silicon takes place, and that there is then little 
or no flame, but chiefly sparks; no carbonic oxide is formed in 
the presence of the more oxidizable silicon. In the same 
manner silicon decomposes carbonic oxide. 

Si+3C0=Si0 3 +3C. 

Silica and carbon are thus the only products of the reaction ; 
the carbon set free is dissolved in the metal and the silica goes 
into slag. 

The action of silicon is thus well defined, and although the 
method of producing sound castings in England and Germany 
has been usually held as a secret (although Mr. Bessemer early 
discovered and published it), we may safely presume that such 
castings are obtained by the addition of silicious pig before 
teeming. But if these steels are without blow-holes, they are 
bv no means adapted to most purposes. The pig obtainable 
before special pig was made was relatively poor in silicon, and, 
in order to be sure that it would act effectively, a rather large 
quantity had to be charged. This produced a highly carburized 
and brittle steel, which also showed the bad effects heretofore 
attributed to silicon, but more properly ascribable to silica.'’ 

The influence of silicon on the mechanical qualities of steel 
has not until lately been very clearly ascertained. To its 
presence, in some Bessemer steels especially, has been attri¬ 
buted a peculiar red-shortness and cold-shortness. A series of 
experiments made by the late Wenzel Mrazek, of the School 
of Mines at Przibram (Bohemia), proved that if a certain 
quantity of good metallic silicon is added to a pure iron, the 
original qualities are not changed. He also showed that the 
action attributed to this ingredient should be ascribed to 


36 


silicate of iron. The silica formed by the burning of silicon 
is changed into silicate of iron, and this silicate, being but 
slightly fluid, remains mixed throughout the mass of metal 
and makes it both red-short and cold-short. 

At Terrenoire this defect was remedied by using the triple 
compound of iron, silicon, and manganese at the time and in 
the proportions mentioned above. The action may be de¬ 
scribed as follows: 

The silicon prevents blow-holes by decomposing the carbonic 
oxide. The manganese reduces the oxide of iron, and prevents 
a farther production of gases by the reaction of this oxide on 
the carbon. But the decomposition of carbonic oxide by 
silicon produces silica, and afterwards silicate of iron, which 
remains incorporated in the steel; the manganese allows the 
formation of a double silicate of iron and manganese, which, 
being much more fusible, readily passes into the slag. The 
metal is thus purified and remains uninjured by interposed 
oxide of iron and slag. . 

In order to show plainly the structural difference between 
steels without blow-holes obtained by silicon alone and 
those obtained by an alloy of silicon and manganese, 
M. Pourcel, the Chief Engineer of the Terrenoire Steel- 
Works, makes the following experiment: In a porcelain tube 
he places two receptacles, one holding steel by silicon alone, 
and the other steel by silicon and manganese ; a current of 
chlorine is passed through them until all the iron is removed 
in a state of chloride. In the first receptacle there remains a 
network of silicate of iron preserving the original form of the 
piece, while in the other there is no residuum. 

The analysis of the steel we are considering shows that a 
considerable proportion of manganese and silicon remains in 
the final product. There is no doubt that these ingredients 
impart to the metal some special qualities. It is therefore 
necessary to conduct the operation in such a manner that the 
chemical composition of the charge may be absolutely known. 
This is the reason why it is indispensable to keep oxidation 
under control during the whole operation, so that the materials 
forming the final additions will perform their desired func- 


37 


tions in the bath, part of the ingredients being absorbed by 
the reactions, while the rest remain in the finished product. 
Should the charge become too much oxidized, it would be im¬ 
possible to ascertain the exact amount of silicon and manga¬ 
nese required to produce the reactions, and the composition 
might be so changed as to make it unfit for the uses to which 
it is to be applied. This point lias been reiterated because it 
is of the highest importance. 

MOULDS AND CASTING. 

The rapid cooling and large shrinkage of steel require great 
care in the preparation of moulds, and especially of yielding 
cores. If steel tends to lie as dead and solid as cast iron—and 
this steel does so—it is nevertheless possible to mould shapes 
and to pour steel in such a way that the castings will be un¬ 
sound. Moulds that are damp, or that are otherwise so com¬ 
posed that they may generate gases when they receive white- 
hot steel, will be likely to cause blow-holes. 

7 v , 

The making of moulds for steel has been brought to great 
perfection in Sheffield and in other places in England, notably 
at the West Cumberland Works, where Bessemer steel cast¬ 
ings are made quite as smooth as ordinary iron castings. But, 
as before remarked, these beautiful castings are not sound 
when they are soft and tough. 

It is a somewhat remarkable fact that the art of moulding 
for steel is to a great extent a secret among the English 
moulders. In many cases the managers and proprietors of 
works know only in a very general way the proportions of 
materials employed, just as in many English rolling-mills the 
management has no drawings nor templets of roll-grooves— 
these are the private property of the roll-turner. The old 
Repie moulding mixture, in which steel castings were first 
made with even approximate success, consisted of calcined fire¬ 
clay with just enough raw clay to make it stick together. 
Old clay pots are now largely used in the place of’ specially 
calcined clay, and the mixture is made slightly open and porous 
by coke-dust, and very refractory Ceylon graphite is often 
added. The whole is ground fine and passed through a sieve. 


38 


The facing is a very important matter. In several works this 
consists of Ceylon graphite and a little china clay. After 
long experience, expert moulders have learned to vary the 
composition and thickness of moulds to suit all thicknesses of 
castings and grades of steel. The above facts are known gene¬ 
rally; each works has its peculiar treatment, and any works 
can secure a good moulder or can perfect a system with a 
little experimenting. 

At Terrenoire the whole practice has until recently been 
the casting of projectiles and simple forms in iron moulds; 
and while hardly the average skill has been attained in 
mineral moulding, many uniformly solid and fairly smooth 
complex castings have been produced. The car-wheels, frogs, 
roll-pinions, bolsters, and other machinery used in the works 
are now cast entirely in steel. The gun-carriage brace before 
mentioned was cast in a mould made of ground-clay pots with 
graphite facing. 

The cast iron moulds used in the manufacture of projectiles 
are made in two superposed sections; the lower section con¬ 
tains the point or rounded part; the upper one the cylindrical 
' part. The use of metallic moulds, besides favoring rapid 
cooling, which improves the metal by stopping in some de¬ 
gree its tendency to crystallize in large and irregular crystals, 
forms part of an improved system of feeding the enormous 
shrinkage of cast steel. Just before casting, a loam-lined 
fountain, capable of holding from to in weight of the 
piece in the mould, is placed hot in its proper position, then 
both the mould and the fountain are filled. The metal in the 
mould cools rapidly on the outside; this cooling spreads b} 7 
degrees throughout the mass from outside to inside; the soli¬ 
dified particles draw away from the centre, and shrinkage 
takes place chiefly in the centre of the casting, which will thus 
tend to become porous—in other words, it will pipe. But 
the large fountain being thicker and hotter than the mould, 
the metal it contains will remain liquid, and, flowing down, 
will gradually feed the shrinkage in the casting. It is well in 
all cases to make the neck of the fountain or sprue as wide as 
possible; for if it is too narrow, the metal might set in it and 




39 


prevent any further feeding. The sprue for a 10-in. projectile 
is 16 in. high and in. in least diameter. Some 5,000 tons 
of projectiles had been made in this maimer up to last winter, 
with uniformly good results. 

This system of a rapidly-cooling mould and a hot sprue or 
fountain—possibly to be kept hot (for large castings) by 
means of a bath of liquid iron or other intense and maintained 
source of heat—is deemed of very great importance by the 
Terrenoire engineers. They were experimenting on very 
heavy iron moulds for cannon when we were at the works, 
and they have, since cast cannon with entire success. I am 
promised details of the moulds and casting appliances and 
practice for cannon. Two 18-ton furnaces were also building ; 
they have recently been started, and 15-ton castings have been 
made; a 28-ton ingot of soft steel for a 3-throw crank-shaft 
has been cast out of the two furnaces. 

ANNEALING. 

A glance at Table A will show the important influence 
annealing exerts on this metal. It will be seen that it not 
only increases the strength within and beyond the elastic 
limit, but that it also improves ductility in a notable degree. 
The average elongation of raw, hard metal is 2.4 per cent., 
while the same metal annealed stretches 8 per cent. The 
difference is still more marked in medium steel ; the average 
stretch of the raw material is 2.7 per cent. ; the annealed 
reaches 14.6 per cent., or more than five times the original 
ductility. This result is due to a change in the crystalline 
state which is characteristic of all ingot metals. In this state 
the structure is loose ; each crystal is an independent mass 
easily detached from its neighbor, and the metal is reduced to 
its minimum strength and elasticity. Inordinary steel, rolling 
or hammering will not only close the biow-holes, but it will 
change the crystallization. In the Terrenoire solid steel, an¬ 
nealing at the proper temperature imparts all the qualities 
due to rolling or hammering ordinary steel. Repeated and 
careful experiments of the most exhaustive character, made at 
Terrenoire, have established this fact beyond a doubt. Further 


40 


proof is found in a paper on the “Structure of Steel,” by M. 
Chernoff (Chief Engineer of the Abouchoff Steel-Works in 
Russia), published July 7, 1876, in Engineering. It relates 
to a series of experiments made at these works, among them 
the following: A coarse-grained, sound cast-steel ingot was 
cut lengthwise in four parts. One of the quarters was cut, in 
a lathe, into a test bar; the second was heated to a bright red, 
forged under a steam-hammer, the forging being stopped 
whilst the piece was yet rather hot (probably cherry-red); 
the third piece was heated up to the point at which the ham¬ 
mering of the preceding piece had been left off, and was 
allowed to cool slowly. The fracture showed a very fine 
grain, similar to that of the forged piece. These two quarters 
were also turned into test bars. 

The results of the tensile tests were as follows : 



Breaking Load. 

Elongation. 

Dynamic 

Resistance.* 

Unforged. 

34.8 

0.023 

0.8 

Forged. 

41.5 

0.053 

1.1 

Annealed. 

38.7 

0.166 

3.21 


The obvious conclusion is that it is possible to make a steel 
in its cast state just as strong as if it had been hammered, 
provided, however, that the metal is regularly without blow¬ 
holes. 

The temperature at which annealing should take place is a 
good cherry-red ; if the temperature is too high, the crystalline 
structure remains, and with it the lack of strength. The 
heating should be very gradual, and cooling must be carefully 
conducted, so as to avoid internal strains. If the final metal 
tests have proved that a charge is rather hard, the pieces must 
remain longer in the annealing furnace. 

When pieces have to be turned and finished, they should be 
first roughed down and then annealed ; the final shape may be 
given afterwards. Projectiles, after annealing, are hardened 
by heating them to a cherry-red and plunging them into oil. 

* Dynamic resistance per cubic inoh in tons. Ultimate strength elongation. 



















41 


The specific gravity of the annealed metal is 7.9—above that 
ot ordinary forged steel, which rarely reaches 7.821. 

TJSE8 OF SOLID STEEL CASTINGS. 

The superiority of this steel, as compared with all other 
materials, for projectiles, has been referred to. The results 
of the very first experiments in casting cannon were still more 
remarkable. During the last summer a gun-tube was cast 
from this metal ; it had 8-in. exterior diameter and a 5-in. 
bore, so that the walls were but 1^ in. thick. The casting 
was simply bored, annealed, and tempered in oil. Some 
specimens cut perpendicularly to the axis of the tube were 
tested August 17 by Col. Maillard, the director of the 
National Gfun Factory at Nevers, with the following results: 



Limit of 
Elasticity. 
Tons per 
Square Inch. 

Tension at 
Rupture. 
Tons per 
Square Inch. 

Elongation. 
Per cent. 

At the back.... 

... .No. 1 

22.0 

42.5 

11.1 

<< 

....No. 2 

22.2 

39.6 

8.7 

In front. 

....No. 1 

22.5 

38.1 

15.1 

i < 

....No. 2 

22.7 

38.5 

15.0 


Several pieces 1]^ in. square and 6 in. long were next sub¬ 
mitted to the shock of a drop weighing 40 lbs., falling from 
increasing heights. The supports were 5 in. apart, and rested 
on an anvil weighing 1,800 lbs. These pieces resisted well, 
and one of them did not break when the ball tell from 8 ft. in 
height, which gave it a bend in the centre ol about 1 in. 

The French Government have specified the following for 
the trials of all steel tubes for the navy : 

Tons per 
Square Inch. 


Limit of elasticity. 21 

Tension at rupture.. 38 


It will be seen from the above that the Terrenoire tube 
answered more than the requirements. For the experiments 
with powder the tube was mounted on a portable carriage, 
after having been placed in a suitable trunnion-ring. 
















42 


Twenty shots were first fired with the ordinary service 
charge of 9 lbs. of powder and a 40-lb. shell; after this, 10 
shots with a shell weighing 47 lbs., and from this time forward 
the charges of powder were successively increased by % lb. 
every ten shots, the shell remaining the same until the 100th. 
shot was fired. At this point the chamber was quite full, and 
the charge had to be rammed in order to get it into place, and 
much difficulty was found in closing the gun. The experiment 
was stopped at this point, as the official regulation test had 
been accomplished. After each 10 shots the tube was washed 
out with care, and measured by means of precise instruments 
in every part. Uo flaw of any kind was discovered, and the 
deformation of the chamber was found to be less than half the 
average in forged-steel tubes. 

Larger tubes will be submitted to trial very shortly ; two of 
them will Iuive an internal diameter of 4 in. only. One has 
been cast of 13 in- outside diameter for a gun the body of 
which will be made of cast steel and will weigh 19 tons. As 
the central tube is the more delicate portion of the cannon, 
there is little doubt of success in casting the body of a “ built- 
up” gun also of steel. 

It should appear, judging from the general character of this 
steel as shown in the final table, added to the results of this gun 
experiment—which is but one experiment, and hence may not 
be considered conclusive—that the American system of cheap 
ordnance—cheap because it is cast—is to be successfully 
realized. If so, it will follow that the just criticism upon the 
standard American gun, that it is comparatively worthless be¬ 
cause it is cast iron , will be reversed. We can hardly con¬ 
ceive a fact of greater magnitude—from a defensive point of 
view—than this: that while the United States has at this 
moment not a single standard type of naval gun, or gun of 
position, that is comparable in efficiency with the guns of 
foreign states, it has, by means of the good policy of its Ord¬ 
nance Department, studied the results of foreign experiments 
and avoided the enormous cost of original investigations; and 
that this policy must now be rewarded by the establishment of 
the cheap cast gun , the metal to be, not crude iron, but steel 


I 


43 


having three or four times the strength, as made according to 
the specification detailed in the foregoing pages. And although 
we have good field guns, the sound-casting system will be 
equally applicable for this purpose also, in view of its economy. 

The protection ot the whole coast of the United States 
(greater than that of any other Power) and its entire interior 
defences, heretofore quite inadequate as compared with the 


protection which steel ordnance provides for other countries— 
this whole problem may now be solved by the perfection of 
the art of solid-steel casting, if, indeed, this art does not raise 
the standard while it largely reduces the cost of armament. 

In 1865 the cost of heavy guns was as follows: 


Armstrong.... 

Krupp . 

Blakely. 

Whitworth.... 
Parrott. 

Rodman.. 

< < 


10.5 in. wrouglit-iron hoop-gun.33.6 cents per lb. 

15-in. solid steel gun. 87.5 “ 

10-in. steel-tube, hooped with steel.... 78.5 “ 

7-in. “ “ “ .... 62.5 

10-in. cast-iron, hooped with wrought 

iron.. 17.0 “ 

10-in. cast iron. 9.75 “ 

15-in. “ .13.2 “ 


The present cost of guns is largely reduced, but the above 
relative costs will hold good, and they show the very notable 
comparative cheapness of the cast gun. The exact cost of 
solid cast-steel guns cannot yet be exactly estimated, but it is 
certain that it will not exceed one-third of the cost of ham- 
mered-steel guns. 

With reference to general machinery, it must be obvious 
that a metal simply cast into’ usable form, and having the 
range of tensile strength from 50 to 30 tons per square inch, 
and the corresponding elongation of 7 per cent, to 28 per 
cent.,* is destined to replace not only iron castings, but iron 
and steel forgings which are several times more costly and no 
stronger. 

The hammering of a large mass of steel—for instance, a 
40-ton ingot for a gun or a marine shaft—is a very costly and 


* It should be remembered that the test specimens of this steel are 
4 inches long, while the reported tests of Whitworth’s compressed steel 
are made on 2-inch lengths, and its 30 per cent, elongation would be con¬ 
siderably reduced if tested on 4-inch lengths. 

(f 


) '? 
.) v 
S > > 


> 











44 


hazardous undertaking. There are but few, if any, hammers 
in the world which can condense such a mass to the core. 
The hammer and tlie special tools are enormously expensive ; 
the new 00-ton hammer plant at Oreusot will have cost above 
half a million dollars. The heating—several days for a single 
heat—and the loss by oxidation, and the wasters due to crack¬ 
ing from inadequate or over heating, are important elements 
of cost. Forging, under the heaviest hammers, reaches only 
the parts in the immediate vicinity of impact; the piece is 
therefore subjected to a series of internal strains, due to the 
difference in the molecular arrangement of adjacent parts. 
Even in the finished piece the same difference in molecular 
structure exists. Each part does not receive exactly the same 
reduction, and crystallization is not equally changed through¬ 
out the mass. It is thus left subject to internal strains which 
may cause ruptures when and where least expected. 

The casting of a piece which has the desired shape and 
requires no reheating beyond a slow annealing, is so great a 
progress, that it must be obvious to all practical men, especially 
when it is considered that the product possesses, in every part 
of its homogeneous mass, all the physical qualities of forged 
steel. 

This metal must therefore come into use for all heavy parts 
of machinery—for shafts, screws, cranks, bed-plates, hydraulic 
cylinders, pinions, frames, gearing, etc., etc. For rolling- 
mills its use is clearly pointed out; its wearing capacity is 
immensely greater than that of cast iron, and its high tenacity 
ensures stability under sudden strains. Housings, rolls, 
pinions, boxes, riders, and, in tact, almost every part of a 
train, could be advantageously made of this metal; and, 
although the first cost might be larger than that of an ordinary 
plant, the economy in repairs and maintenance would soon 
prove a compensation. 

Railroad engineers will find this metal adapted to many 
uses within their province. Frogs, crossings, car-wheels, 
driving-wheels, cranks, axles, and parts of framing can be, 
made of it, with economy in weight and increase of duration. 

The softest grades of this metal, say 30 tons per sq. in. 


45 


with 30 per cent, elongation, seem eminently fitted for the 
manufacture of armor-plates for ships and forts. The late 
Italian experiments on plates of steel of this grade versus 
iron have already proved the superiority of steel. The ad¬ 
vantages are numerous. The plates can be cast so as to 
conform to the shape of the ship; they can be made hollow, 
having a space, which recent experiments have proved most 
useful, between the inside and outside walls, and bolt-heads 
and other modes of attachment to the hull can be concealed. 
Besides this, the plates can be made of unlimited thickness. 

The use of steel in construction has so far been greatly 
hampered by the difficulty of bringing it to its final shape. 
Its behavior is so unlike that of iron that workmen have to be 
specially educated to manipulate it. The building of steel 
ships in the French dock-yards, as described in detail by M. 
Barba,* proves that rolled and hammered pieces must be 
repeatedly annealed during the operations of manufacture. 
On account of its hardness, several reheatings, with their ac¬ 
companying waste and risk, are necessary to bring steel into 
difficult rolled shapes, such as I-beams. These embarrassments 
are obviously remedied by casting the metal at once into the 
desired shape. 

This steel is readily welded, on account of its large percent¬ 
age of silicon, which in oxidizing makes an ever and intimately 
pr esent flux. The advantages of welding a casting to a rolled 
or forged bar will be appreciated by machine-builders. 

It seems eminently proper, before closing this monograph, 
to mention with praise the gentlemen who have developed the 
remarkable process which we have described, and, in so doing, 
to state again the grounds of its novelty, which they have, 
with so much painstaking experiment, developed and per¬ 
fected. 

It is true that steel castings have been previously made 
which have possessed some, but not all, of the physical charac¬ 
ters which the Terrenoire solid-cast steel embodies. These 
other steels have not, for instance, combined softness with 

* Translation published by Van Nostrand, New York. 


46 


soundness; they have not been both hard and malleable; and 
they have not possessed a high specific gravity. Even where 
these previous castings are found to contain silicon or manga¬ 
nese, or both, these ingredients have occurred in different 
proportions from those used at Terrenoire. Some years of 
experimenting prove that, without the reduced oxidation of 
the bath, and without the final addition of silicon and manga¬ 
nese in substantially the proportions described, a cast metal 
possessing the physical qualities described cannot be produced. 
The Terrenoire process is thus novel in the following particu¬ 
lars : 1st. It employs manganese and silicon in definite 
proportions and in a combination for definite purposes. 2d. 
It employs them at regulated times during the operation, in 
order that the reactions which have been mentioned may 
occur. The invention is, therefore, not a modification of any 
previous accidental use of silicon and manganese at indefinite 
times, but it is a consecutive system of times and amounts of 
application of these ingredients, to bring about results not 
heretofore known, sought, or realized. 

The development of this most remarkable and truly scienti¬ 
fic manufacture has been due to the combined efforts of Mr. 
Yalton, an eminent metallurgist (who proved himself to be a 
discriminating judge at our Centennial Exhibition*); of Mr. 
Euverte, the General Manager of the Terrenoire Works, who 
had such a correct technical knowledge of iron metallurgy 
that he not only allowed the Company’s money to flow for 
years into the preliminary experiments, but that he contributed 
to the technical result; and, 1 believe, chiefly of Mr. Pourcel, 
the Chief-Engineer of the Terrenoire Works, whose thorough 
training in investigations concerning the chemical and physical 
properties of steel, and whose enthusiasm, which was never 
checked by the discouraging results of early experiments, not 
to speak of the special adaptation of his mind to metallurgical 
research, have eminently qualified him to conduct and to perfect 
the remarkable product which in France is known as acier 
sans soufflures. 


* See his official report to the French Government. 


INGREDIENTS, ANALYSES, AND MECHANICAL TESTS OF SOLID STEEL CASTINGS. 











i 

Number of 



' 




1 

1 


Materials forming the charge—Pounds. 



hammer- 

blows 

Percentage of ingredients intro- 

Chemical analyses made on the 










duced, with the final 


product before an- 












additions. 




nealing. 


Num- 









to break a 






Spiegel, 

Besse- 

Soft- 

Purl- 

Special 




test-piece 








ber of 
the 

charg’s. 

7 to 8 
per ct. 
Mn. 

mer 

rail- 

ends. 

steel 

died 

Ferro- 


of 

hammered 

metal. 








borings 

iron. 

pig- 

manganese. 


Mn. 

C. 

Si. 

Mn. 

C. 

Si. 

*1996 

500 

4400 



540 

100 525 Mn. 


4-1 

1.30 

0.408 

0.415 

> 




*2004 

500 

5200 



620 

90 

11 


3-2 

1.05 

0.380 

0.410 





*2007 

500 

4400 



540 

100 

66 


6-7-8 

1.30 

0.408 

0.415 


Average analysis : 

2035 

700 

4600 



600 

108 

66 

G0 

4-4 

1.31 

0.415 

0.425 


f 0.945 

0.560 

0.340 

2038 

700 

4400 



560 

100 

l 6 


4-2 

1.265 

0.403 

0.412 





*2051 

700 

4800 



594 

108 

66 

o 

<X) 

5-11 

1.26 

0.403 

0.410 





*2071 

600 

4400 



600 

90 

66 

c* 

2-13 

1.215 

0.420 

0.445 

< 




*2074 

600 

4400 



600 

88 

6 i 

p. 

16-9 

1.215 

0.420 

0.445 





2112 

700 

4000 



564 

86 

66 

u 

3-3 

1.25 

0.425 

0.448 





*2124 

600 

4400 



600 

106 

66 

*+H 

4-3 

1.18 

0.415 

0.450 





2130 

700 

5200 



708 

106 

66 


5-4-9-6 

1.21 

0.417 

0.448 





2138 

500 

4400 



588 

90 

6 6 

CD 

a 

7-1 

1.22 

0.418 

0.448 


Average analysis : 

2145 

500 

4400 



588 

88 

66 

2-2 

1.21 

0.416 

0.448 


[ 0.880 

0.500 

0.390 

2168 

500 

4400 



588 

86 

66 


8-5 

1.19 

0.415 

0.448 





2179 

500 

4000 



540 

SO 

66 

a 

5-5 

1.175 

0.417 

0.448 





2230 

800 

5214 



720 

104 

66 

6-7 

1.175 

0.414 

0.448 





2237 

500 

4080 

830 


672 

94 

66 


8-4 

1.115 

0.425 

0.462 





2259 

800 

5200 



720 

112 

66 


9-4 

1.24 

0.420 

0.450 

J 





Spiegel 
12 per 
ct. Mn. 
















2078 

400 


1400 

1200 

126 



cS 

Bent. 

6.30 

0.0725 

0.340 


0.420 

® o 
*LZO 

03 T-t 

0.203 

2081 

400 


1400 

1200 

120 

14 7 

7%Mn. 

3 

66 

8.35 

0.0885 

0.290 


0.660 

0.263 

2149 

400 


2000 

1600 

160 

13 

66 


66 

8.10 

0.0835 

0.300 


0.610 

CL O 

V 1 

0.233 

2208 

580 


1000 

2010 

144 

13 

66 

Xfl 

66 

8.40 

0.0860 

0.300 


0.630 

0.209 


OBSERVATIONS. 


Fihst Series.— Proportion in weight of materials introduced at tlie end of the operation : 

Special pig=l\ per cent, of the charge already in the furnace. 

Metallic manganese=l.3 per cent, of the whole charge, including special pig. This proportion of metallic manganese 
consists partly of the manganese contained in special pig and of a supplementary quantity introduced in the shape of 52 % 
ferro-manganese. 

Second Series : 

Special pig —12 per cent, of the charge already in the furnace. 

Metallic manganese=1.2 per cent, of the whole charge, including special pig, as above. 

Special pig used in projectile charges. — Mn.=3.50; Ch =3.00 ; Si.=4.20; P.=0.100. 

Special pig used in soft-steel charges. —Mu. =14.00; C. =1.00; Si. =7.50; P. =0.125. 


Tensile Tests.—Length of test-bars—4 in. Section—0.232 sq. in. 








Metal heated to cherry-red and cooled 

Drop-tests on 


Annealed metal. 



in oil. 


annealed metal 

L. 

B. 

C. 

E. 

L. 

B. 

C. 

E. 




23.65 

23.24 

23.17 

47.30 

47.94 

45.08 


8.00 

8.75 

7.50 




5.60 

6 

6 

6 

ft. 

ft. 

ft. 

4% in. 
10% Id. 
4% in. 

24.32 

46.03 


6.20 

26.03 

50.29 


6 

ft. 

4% iD. 

22.98 

46.03 


4.00 

26.03 

53.97 


6.80 

6 

tt. 

2% in. 

22.98 

46.35 


13.00 

22.98 

50.41 


12.20 

7 

ft. 

8% in. 

21.27 

46.35 


10.00 





7 

ft. 

0% in. 

21.27 

46.35 


10.80 




7.30 

6 

ft. 

8% in. 

21.27 

48.38 


9.00 

29.90 

52.70 


6 

ft. 

8% iD. 

99 QM 

48.38 

m 

11.50 

30.34 

57.15 


5.50 

7 

ft. 

0% in. 

23.17 

50. SO 


7.70 

29.27 

56.38 


7.80 

6 

ft. 

ft. 

8% in. 

22.86 

50.48 


11.30 

27.94 

50.80 


8.40 

7 

10% in. 

21.59 

47.94 


9.30 

29.71 

53.34 


7.00 

6 

ft. 

10% in. 

22.86 

49.53 


7.90 

26.03 

50.67 


7.50 

6 

ft. 

6% in. 

21.52 

44.45 


8.10 

26.67 

47.75 


7.00 

6 

ft. 

6% in. 

21.09 

47.75 


11.50 





6 

ft. 

8% in. 

22.86 

50.03 


7.60 





6 

ft. 

8% iD. 

22.86 

50.48 


7.50 





6 

It. 

8% in. 









Not 

broken, 











at 

14.73 

31.24 

45.00 

28.50 

24.25 

39.43 

35.00 

15.00 

8 

ft. 

2% in. 

17.00 

32.38 

43.50 

25.60 




19.50 




12.70 

29.00 


26.70 

18.79 

3S.10 





15.11 

31.94 


24.30 

20.00 

34.98 


16.00 





OBSERVATIONS. 

L represents the load per square inch (in 2,240-lb. tons) necessary to bring the 
test bar to its limit of elasticity. 

B is the breaking load. 

C is the percentage of contraction. 

E is the percentage of elongation measured between two points 4 inches apart. 

The drop-tests are made with bars 1-fV in. square. The bearings are 6-,^- in. apart. 
The drop weighs 39% lbs. This at first falls from a height of 5 ft. 10% in., and is 
raised 2 inches higher every time. 

10-in. projectiles from charges marked thus * go through an 8-in. armor-plate 
inclined at 30°, with an original speed of 1,332 ft. 

Also, through an 8j^ in. armor-plate inclined at 20 , with original speed of 
1,394 ft. 

















































































































































